require_organization_field.js

$(document).ready(function() {
  var organizationLabel = $('label[for="subscription_customer_attributes_organization"]');
  organizationLabel.text(organizationLabel.text() + " *");
});

var form = $("#signup-form");
var organization = $("#subscription_customer_attributes_organization");
var submitBtn = $("#subscription_submit")

submitBtn.click(function() {
  if (organization.val() === "") {
    organization.addClass("field-error");
    return false;
  }
});

form.change(function(){
  if (organization.val() != "") {
    submitBtn.click(function() {
      return true;
    });
  }
});

$("#subscription_customer_attributes_organization").blur(function() {
  if ($(this).val() !== "") {
    $(this).removeClass("field-error");
  } else {
    $(this).addClass("field-error");
  }
});

.field-error {
  border-color: #ff0000;
}